Search results for "chemistry [Water]"
showing 10 items of 2369 documents
Current challenges supporting school-aged children with vision problems: A rapid review
2021
Contains fulltext : 240193.pdf (Publisher’s version ) (Open Access) Many children have undetected vision problems or insufficient visual information processing that may be a factor in lower academic outcomes. The aim of this paper is to contribute to a better understanding of the importance of vision screening for school-aged children, and to investigate the possibilities of how eye-tracking (ET) technologies can support this. While there are indications that these technologies can support vision screening, a broad understanding of how to apply them and by whom, and if it is possible to utilize them at schools, is lacking. We review interdisciplinary research on performing vision investigat…
How to Prevent SARS-CoV-2 Transmission in the Agri-Food Industry during the First Pandemic Wave: Effects on Seroprevalence
2021
During the SARS-CoV-2 pandemic, many workplaces were forced to interrupt their activities or alternatively had to prefer a smart way of working, if this was compatible with their activities, to contain the spread of the virus. Some production activities, on the other hand, continued, such as those belonging to the agri-food sector. The aim of the study was to investigate seroprevalence in the workers of an Italian agri-food company following prevention interventions developed in concert with an occupational physician. An observational cohort study was conducted on a population of 328 (100%) workers of a company in the agri-food sector, located in the Sicilian region, which specialized in th…
Intra-Articular Hybrid Hyaluronic Acid Injection Treatment in Overweight Patients with Knee Osteoarthritis: A Single-Center, Open-Label, Prospective …
2021
Background: A BMI >
ETAS Space–Time Modeling of Chile Triggered Seismicity Using Covariates: Some Preliminary Results
2021
Chilean seismic activity is one of the strongest in the world. As already shown in previous papers, seismic activity can be usefully described by a space–time branching process, such as the ETAS (Epidemic Type Aftershock Sequences) model, which is a semiparametric model with a large time-scale component for the background seismicity and a small time-scale component for the triggered seismicity. The use of covariates can improve the description of triggered seismicity in the ETAS model, so in this paper, we study the Chilean seismicity separately for the North and South area, using some GPS-related data observed together with ordinary catalog data. Our results show evidence that the use of s…
Multi-Technique Diagnostic Investigation in View of the Restoration of “The Glory of St. Barbara” Painting by Mattia Preti
2022
The present paper illustrates the results of a diagnostic investigation performed on the oil on canvas painting “The Glory of St. Barbara” (1680–1688) by Mattia Preti. The painting is located inside the St. Barbara Church in Taverna (Catanzaro, Italy), the city that gave birth to the artist. In situ, non-invasive studies, by applying X-ray fluorescence (XRF) spectroscopy, along with laboratory micro-destructive analytical investigations, by employing electron probe microanalyses (EPMA) coupled with energy-dispersive spectrometry (EDS) and micro-Raman (µ-Raman) spectroscopy, were combined to retrieve the color palette and identify the painting technique and style of t…
Duvalo “Volcano” (North Macedonia): A Purely Tectonic‐Related CO 2 Degassing System
2022
Duvalo “volcano” is a site of anomalous geogenic degassing close to Ohrid (North Macedonia) not related to volcanic activity, despite its name. CO2 flux measurements made with the accumulation chamber (321 sites over ∼50,000 m2) showed fluxes up to nearly 60,000 g m-2 d-1, sustaining a total output of ∼67 t d-1. Soil gas samples were taken at 50 cm depth from sites with high CO2 fluxes and analyzed for their chemical and isotope composition. The gas is mainly composed by CO2 (> 90%) with significant concentrations of H2S (up to 0.55 %) and CH4 (up to 0.32 %). The isotope compositions of He (R/RA 0.10) and of CO2 (δ13C ∼0‰) exclude significant mantle contribution, while δ13C-CH4 (∼ -35‰) …
Erratum to “First description of a metamorphic sole related to ophiolite obduction in the northern Caribbean: Geochemistry and petrology of the Güira…
2014
Green determination of the presence of volatile organic compounds in vehicle repair shops through passive sampling.
2012
A simple, fast and green direct analytical methodology has been developed to evaluate the concentration level of volatile organic compounds (VOCs) in indoor areas of vehicle repair shops using membrane devices as passive samplers. VOCs retained in the samplers were directly determined without any sample pre-treatment and avoiding the use of solvents by head space (HS) coupled to gas chromatography-mass spectrometry (GC-MS) in only 20 min. Benzene, toluene, tetrachloroethene, m,p-xylene and o-xylene were found at concentration levels from 0.1 to 11.2 mg m(-3).
Reflections on the Nature of the Periodic Table of the Elements: Implications in Chemical Education
2014
The periodic table of the elements (PTE) results essential to understand our nature and place in the whole of beings. The same happens with our food, drugs, materials, etc. A series of questions were asked to introduce PTE and provide answers. The ideas in PTE should be valued by the number of questions that they generate. The PTE was related to electron configurations. The emergence of elements (nucleosynthesis) in physics was explained. The PTE results essential to understand our nature and place in the whole of beings. The same happens with our food, drugs, materials, etc. Schwarz and Rich asked a series of questions (Qs) to introduce PTE and provided answers. The ideas on PTE should be …
Surface properties and catalytic performance for ethane combustion of La1−xKxMnO3+δ perovskites
2001
Abstract The influence of K substitution in LaMnO3 perovskite on the surface properties and catalytic oxidation of ethane has been studied. La1−xKxMnO3+δ perovskites (x=0.05, 0.10, 0.15, 0.20 and 0.25) with BET surface area of 20–26 m2 g−1 have been prepared by the freeze-drying method and characterized by X-ray diffraction patterns (XRD), TPR, TPD and XPS. The XRD analyses showed the presence of a single crystalline phase (x≤0.15) with the linear increase of the lattice parameter corroborating the incorporation of potassium in the perovskite structure. The XPS studies revealed an enrichment of the perovskite surface with potassium accompanied by an increase in the surface Mn4+/Mn3+ ratio. …